Estimation of excess life cancer risk and annual effective dose for boreholes and well water in Dutse, Jigawa State Nigeria

Abstract

The level of 222Rn concentration for water samples collected from twenty-two (22) water samples in Dutse Local Government, Jigawa State, Nigeria was determined using liquid scintillation counter (Model: Tri-CarbLSA1000). Borehole and local hand dug wells are the two sources of water been collected. Also, an attempt was made to estimate the Excess Life Cancer Risk and Annual Effective Dose due to Ingestion for different ages groups. The mean value of 222Rn concentration were found to be 82.7461 and 94.10771 BqL^-1 for boreholes and well water samples respectively. All the mean values are above the maximum concentration level set by UNSCEAR; WHO, but below European commission of 100 BqL^-1. The resulting mean annual effective doses due to ingestion of radon in the water samples for infants, children and adults, were1.057081 and 1.202226 mSvy-¹, 0.90607 and 1.030479 mSvy^-1 and 0.604047 and 0.686986 mSvy^-1, respectively. Also, the resulting mean Excess life cancer risk due to ingestion in borehole and well water sample for adults, children and infants were 2.114E-3 and 2.37 E-1, 3.171 x 10^-3 and 3.61 E-3 and 3.7 E-4 and 4.21 E-3 respectively. All the values were found to be above the maximum concentration level for drinking water and domestic purposes. as set by UNSCEAR, WHO, EU and USEPA. From the radiological point of view, this study indicates that water resources around Dutse Local Government Area Jigawa State were not safe for domestic purposes and drinking.